A Quick Analysis Method For Electromagnetic Problems Of Periodic And Quasi-periodic Metal Structures

The large-scale periodic and quasi-periodic structures are widely used in the field of microwave millimeter antennas and metasurface due to the superior electrical performance that a single element does not have.The full-wave simulation of large array structures is too costly.Therefore,in some application backgrounds,it is very important to study how to improve the efficiency of the solution.In this paper,the fast analysis methods of large metal periodic array structures are studied from the two directions,they are infinite and finite periodic array respectively.The former is an efficient estimation method,and the latter is an accurate and fast analysis method.In the first part,the periodic fast multipole algorithm(P-FMM)was studied to analyze the infinite metal periodic array structure.From the perspective of the physical meaning of the periodic Green's function,the addition theorem of the periodic Green's function and the plane wave expansion form are derived.The realization process of the aggregation,transfer and configuration in the far field action term are discussed in detail.To solve the low frequency collapse in which the group size is too small,an approximate diagonalization method is introduced,which realizes the simple and effective low-frequency fast multipole algorithm of the periodic Green's function.The second part mainly uses the characteristic modes method to analyze the metal periodic array structure accurately and quickly.The global basis functions composed of different characteristic modes are used to greatly reduce the number of unknowns.Through using the repeatability of the array and the fast multipole algorithm,supplemented by computer parallel technology,the calculation efficiency is greatly improved.Then,the combination method of characteristic modes and domain decomposition is proposed to solve the boundary continuous problem and break the grid conformal constraint so that the characteristic modes method is suitable for the fast analysis of broadband quasi-periodic arrays.The proposed method ensures the stability and efficiency of the calculation.Examples are provided to verify the accuracy and efficiency of the proposed method for the rapid analysis of metal periodic array structures.